Christopher Erasmus, completing a master’s in electrical and electronic engineering, has developed an award-winning solar-powered wireless dendrometer and environmental sensing system for the forestry industry. 

This device accurately tracks tree growth patterns, water dynamics, and environmental stressors such as temperature, humidity, and soil moisture. It offers a cost-effective, low-maintenance solution, reducing the need for human intervention while ensuring consistent accuracy and reliability.

Eucalyptus is the most widespread hardwood in the world, and plantations have emerged as a critical global resource, spanning nearly 20 million hectares globally. The wood is a crucial global resource, offering raw materials for renewable energy sources, recyclable fibres, joinery and furniture products. 

As the demand for these resources grows, monitoring and managing Eucalyptus forests sustainably is essential. Erasmus developed a dendrometer and environmental sensor system to assist the monitoring process. A dendrometer measures variations in tree stem diameter over time, including short-term diurnal fluctuations and long-term growth trends. 

During the day, stomata in leaves open, allowing transpiration, the process by which water is lost from the tree to the atmosphere. Due to the development of negative pressures in the conductive xylem (wood), as the rate of water loss often exceeds the rate of water uptake from the roots, this water loss causes a temporary reduction in stem diameter. At night, when the stomata close, the tree equilibrates with the soil, and the stem diameter expands. 

Chris worked with Dr Dave Drew and Eucxylo to develop a generic point dendrometer to measure these variations. EucXylo, a Research Chair funded by the Hans Merensky Legacy Foundation, focuses on the ecophysiology, growth, and wood formation in eucalypts.

Erasmus developed ten wireless dendrometers and environmental sensor systems. He deployed them on Eucalyptus trees, six in Stellenbosch, South Africa, and four in Leiria, Portugal. 

They measure tree stem growth and air and soil conditions and transmit data via LoRaWAN to a cloud-based platform (ThingSpeak) with local SD-card backups. Nine systems collect data at six-minute intervals, while one collects at 11-minute intervals. 

The use of LoRaWAN technology for near real-time data transmission is a novel system feature, providing immediate insights into environmental conditions and tree growth. The capability allows for timely data collection and analysis, crucial for dynamic and responsive research and management practices. It also eliminates the need for cables, which can be a limiting factor for infield experiments. 

The dataset provides comprehensive measurements of tree stem growth, offering valuable insights into the growth rates, patterns, and overall health of Eucalyptus plantations. This detailed data allows researchers to track how trees develop over time and how they respond to different environmental conditions. 

By collecting data from South Africa and Portugal, the dataset allows for comparative studies of Eucalyptus growth across different geographical regions and climates. This comparison can reveal how regional environmental conditions influence tree growth and health, contributing to more informed global forestry practices. The trees in the different regions are also of various ages and sizes. 

The dataset is a valuable resource for future research in forestry, environmental science, and agricultural studies. It offers a solid foundation for further investigations and practical applications in these fields.

Source: Erasmus, Christopher & Booysen, M.J. (Thinus) & Drew, David. (2024). Dataset of dendrometer and environmental parameter measurements of two different species of the group of genera known as eucalypts in South Africa and Portugal. Data in Brief. 57. 111035. 10.1016/j.dib.2024.111035.